1. Field
This disclosure generally relates to displaying three-dimensional models.
2. Background
A geographic information system (GIS) is a system that can be used for storing, retrieving, manipulating, and displaying a three-dimensional model. The three-dimensional model may include satellite images texture mapped to terrain, such as mountains, valleys, and canyons. The GIS uses a virtual camera to navigate through a three-dimensional environment. The virtual camera defines what portion of a three-dimensional model to display to a user in a display area.
A client device may display the three-dimensional model in a geographic information environment. The three-dimensional model may have any number of level-of-detail (LOD) representations that may be displayed in the geographic information environment. Accounting for an LOD of a three-dimensional model may increase or decrease the complexity of a three-dimensional model as a virtual camera moves closer to or farther from the model.
Texture is applied to a surface of the three-dimensional model to give the three-dimensional model a more realistic appearance. When a user switches from a higher resolution model to a lower resolution model the appearance of the texture applied to the lower resolution model may vary significantly. The geometry of the lower resolution model is simplified and includes fewer vertices than the higher resolution model. Accordingly, it may be computationally inefficient to apply the texture used for the higher resolution model to the lower resolution model.
Further, texturing of coarse resolution models is inefficient in space and time because each tile in the model spans a large area and thus may require many source aerial images (e.g., 1000 images). For example, each source image may require computing and storing a corresponding depth buffer for occlusion handling.